[Thud]

Check out Catastrophe: A Quest for the Origins of the Modern World by David Keys, about a titanic volcanic eruption in the Java-Sumatra area about 535 A.D. He has much to say on this subject.

[blam]

"Check out Catastrophe: A Quest for the Origins of the Modern World by David Keys"

I read that.

I like the explanation by professor Mike Baillie in his excellent book, Exodus To Arthur
Although the trees worldwide record a catastrophic event at that time, Baillie explains that there isn't an acid layer (at this time) in the Ice Core samples that is indicitive of a volcano. He argues for a celestial event.

"The five harshest environmental events showing in the dendrochronology records are events at 2354-2345 BC, 1628-1623 BC, 1159-1141 BC, 208-204 BC, and 536-545 AD. In terms of climate, these time periods appear similar in that the growth ring evidence implies colder than usual temperatures and unusual rainfall patterns."

I believe the 1168BC event was the Exodus period and when Santorini/Thera/Akatori in the Mediterranean blew it's top.

[SunkenCiv]

a couple related to the 6th century:

Catastrophic event preceded Dark Ages - scientist
Miscellaneous News Keywords: SCIENCE HISTORY IMAGINATION
Source: Reuters
Posted on 09/08/2000 10:06:44 PDT by VadeRetro
http://www.freerepublic.com/forum/a39b91ca42b27.htm

Astronomers unravel a mystery of the Dark Ages
EurekAlert ^ | 3-Feb-2004 | Dr Derek Ward-Thompson
Posted on 02/03/2004 2:54:24 PM PST by ckilmer
http://www.freerepublic.com/focus/f-news/1070892/posts